Furnace-grate-bar construction



(Yet. 25, 1927.

D. MELLOR FURNACE GRATE BAR CONSTRUCTION Filed April. 23, 1925 04' we. 2-2. F/aJ- gwu'nko'o 1762772515 .W/e/Zor Patented Oct; 25,1927a DENNIS MELLOR, 0F rnrLann-ilrnm, PENN-s1 v NIA, Assrenon or oNEQnALF "r0 ALEXANDER GALE, or rm AnELrn-IA, PENNSYLVANIA.

FUnNAcE-erwrn-B An countr men.

2 Application filed April '23,?1925. Serial No. 25,324..-

The present invention relates to the promotion of co'mbustionot fuel in furnaces and more particularity to 'an improved gratebar Structure. f

some of the objects of the present invention are toprovide a grate bar construction whereby the enter mg air is so proportioned as'to produce perfect and complete combustion of the gases in a furnace; to provide struction. 4o

a furnace structure wherein the discharge of smoke is eliminated; to provide a grate structure which increases the combustion area of a furnace so thatbetter diffusion and chemical combination of thegases, air and smoke take place before leaving the fur nace; to provide a'grate bar which is arranged to deliver air at the front of 'the' bridge wall. to mix "with and ignite'gas and smoke otherwise escaping to the stack; to provide means for maintaining the grate bars of a furnace at a relatively low temperature; to provide a grate'bar structure havingits front end located directly" in the path of the entering air; and to 'provide other improvements as will hereinafter appear.

"In the accompanying drawings Fig. 1 represents a longitudinal, sectional elevation of a furnace showing a grate bar construction embodyingone form of the present ingen of Fig.1;Fig. 3 represents a detail in part section of'a grate barend; Fig. 1 represents a detail in section of the meeting ends of the grate bar sections; Fig.5 represents atrarisverse section of'a grate bar embodying an- "other form of, theinvention; and Fig. '6 rep-. resents a modified form of grate bar con- Beferring to the drawings, a'grate 10 enibo-dying one form of the present invention 1 sv shown in Fig. 1 installed below the boiler 11- I which is mounted as a part of a furnace having a combustion chamber 12, ash pit 13;, a bridge 'wall 14-,- a firing O-pe'ning 15, and a draft opening 16. The grate 10 is arranged to be supported 'at its ends respectively on the usual transverse grate supporting bars 17 and 18 while the central portion thereof is carried by two spacedbars 19 which also extend transversely of the furnace, but atasub- 1 stantially' lower level than the bars 17 and The preferredform or grate bar embodying the presentvinvention is "formed of two sections 20 and 21-p1ac'e'd in end to end relation 'to form complete bar extending lengthwise "or th'e'ifurnace. The front grate bar, section '20 is formed with an upwardly curved'neck 22 with wallsterininating in forward extension23 arranged to seat npon the supporting bar 17, the construction being such that the neck 22 lowers the body part or the bar considerably b elowwh at would be its level as determined by the bar. 17'. I'Also this loweredposition of the grate bar brings its forward end below the bar 17.so that {itfis' directly in the path "or the'air entering by "way or the opening l6. The extension 28 is provided with a laterally disposed lug 2 1 which properlyspaces one bar from another. At the opposite end of the barsection a lug 25 also laterally disposed is provided for spacing purposes having a depending lip '26 to engage one of the cross bars 19 to'hold the grate section in pro er position.

The grate bar section 21, where it engages the other cross bar 19, has a laterally disposed lug 27-with a lip ,28 hooked over the aforesaid bar 19 to properly support and position the end of the bar section 21. *At the opposite end of the "section 21 there is an upwardly curved-neck 3'0Ihaving Wallsbar 18 and having its face abutting" the face of thebridge wall 14. In connection with the head 31 it should be noted that its top terminating in ahead 31 sup 'aorted on'the "edge 82 curves upwardly 'and re'arwardly to form a slightly elevated rear fuel bed in close proximity to the top of the bridge wall, while the latter is formed as an upwardly and rearwardly inclined surface 33 which merges into the edge 82 at its lower part. Thus the surface 33 and the grate bar edge 32 at it's rear form apart of 'the'saine incline, oneb'eing a continuation ofthe other, whereby the bridge wall top can be readily'cleaned and clogging at the bridge throat of the combustion chamber prevented. For maintaining the grate bars relatively cool and for supplying air "-in a preheated state to the combustion chamber the sections of 'e'ach'grate bar are formed with a groove '34 extending throughout the length of each section and of a depth, widtl'i and shape to ill form two relatively long, thin sides which have the general effect of elongated fins exposed to the cooling air to conduct the heat away from the body of the grate bar and so keep its temperature down. The two sections of each grate bar are maintained in end to end alinement by a lug 86 projecting lat erally from the end of one section and in such a position as to enter the groove 34 of the other section where it hasa snug lit to prevent displacement of one section with respect to another. V l

In order to deliver the air, which is heated by its passage through the groove 34, to the combustion chamber at the place where it most effectively promotes combustion, the head 31 on the section 21 is formed with a vertical slot 37 which communicates with the rear end of the groove 84 and thusvprovides an outlet passage for discharging the air into the combustion chamber at substantially the entrance to the throat formed by the bridge wall 14. The efiect of the heated air discharging at this location is to introduce fresh oxygen into the smoke and gases leaving the combustion chamber so that a fresh mixture is formed which immediately ignites I and completes the combustion of what would otherwise be wasted and discharged. as smoke. c

In the form of the invention-shown in Fig. 5 a grate bar 40 of sectional construction is provided generally similar to that already described except in this instance each of its sections is subdivided on a vertical plane passing through its longitudinal axis into two complemental parts 42. These parts are provided on their meeting faces with spacinglugs 43 whereby the proper relative as semblage of the grate bar parts by fastening bolts 44 and 45 forms a complete unitary section having a longitudinally arranged slot 46 in its bottom portion. This construction provides an economical way to manufacture the grate bar sections and gives very accurately fitting parts. I

In someinstances itmay be desirable to regulatethe amount of preheated air delivered through the passage or slot in the grate bar and to that end a damper or valve memher 47 is pivoted as seen in Fig. 6.to two of the grate bars by means of depending brackets 48 and extends transversely across the grate below the neck 31. An arm 50 attached to theaxis of the damper 47 trans- ,mits motion of an operating rod 51 which extends to an accessible point atthe front ofthe furnace. By shifting the rod 51 the position of the damper47 can be varied at will to proportion theamount of air delivered to the furnace in accordance with conditions. V

From the foregoing it will be apparent that a complete unitary grate bar construction has been provided whereby all the gases 7 stack.

the tops thereof are consumed and the discharge of smoke eliminated. Furthermore by forming the bars with a depressed central or body-part an increased depth of fire box is obtained which gives additional burning area and minimizes the escape of heat units to the This depressed grate bar construction brings the inlet ends of the grate bar slots into the path of the entering draft air, and the latter is thereby caused to flow straight through the slots, absorbing heat from the walls and finally passing upwardly through the rear heads to discharge into the chamber along the bridge Wall line. This regulation of "air, preheating and mixing, contributes to a clinker free grate since it prevents the adherence of clinkers and providesa durable and readily cleaned grate structure. It should be noted also that the air passing along under the grate bars from front to rear and discharging in a heated condition at the rear creates an extra draft which maintains a working circulation and produces an intense flame:

lVhile only three forms are shown in which this invention may be embodied, it is to be understood that the invention is not limited to any specific construction, but mightloe applied to various forms without departing from the spirit of the invention or the scope of the appended claims.

Having thus described my invention, I claim:

1. In a furnace grate bar construction, an intermediate and end support bars for grate bars arranged in spaced relation with the intermediate support substantially below the level of both end supports, a plurality of sectional grate bars positioned on said supports with the sections of each grate bar ar ranged in end to end abutting relation over the intermediate support, an upturned portion on each of the non-abutting ends of each grate bar section and extending above the top of the grate bar, said upturned portions being formed for seating engagement on said end supports substantially at'the level of the top of the grate bar, flanges of uniform solid construction depending in parallel spaced re lation from the opposite side edges of each of said grate bar I i and defining a deep air passage groove continuous from end to end of g the. grate bar, one of the upturned end por- 2. In a furnace grate bar construction, the

combination of a support for thefront end of a grate bar, a gratebarhaving a grate sections considerably belows the bar extending considerably below that of-April, 1925.

' 1,64=6,7OO I V a 3 surface and being formed with an upturned bar and open at the front end beneathsaid front end engaged with said support in such support. v w a manner as to dispose the grate surface at Signed at Philadelphia, ,county of Philathe level of said support Withthe body of delphia, State of Pennsylvania, this 20th day" level, said body being formed with a deep x I i bottom opening groove longitudinally of the v DENNIS MELLOR. 

